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Aerodynamic characteristics of membrane airfoil compared to rigid naca 4412 airfoil

Aerodynamic characteristics of membrane airfoil compared to rigid naca 4412 airfoil / Chan Min Xhao

Abstract Membran airfoil dikatakan mempunyai fleksibiliti untuk mengubah geometri permukaannya untuk menyesuaikan diri dengan aliran udara. Ini bermakna ia berpotensi untuk mengimbangi tekanan udara yang tidak seimbang, membantu untuk melambatkan proses stalling dan juga keupayaan untuk mengembangkan cambernya untuk meningkatkan lif keseluruhan. Kertas ini bertujuan untuk mengkaji prestasi airfoil (NACA 4412) yang dibalut dengan selapis getah yang nipis dari segi aerodynamik dan membandingkannya dengan airfoil asal yang keras. Hasil daripada eksperimen yang dijalankan pada Reynolds number, Re = 30,000 ~ 100,000 menunjukkan bahawa nisbah lif-to-drag daripada membran airfoil bertambah baik apabila dibandingkan dengan airfoil asal. Disebabkan ciri-ciri membran yang berunsur lemah, aliran udara yang tinggi adalah tidak sesuai. Daya unsur aerodynamik akan diukur menggunakan ‘external force balance’ dengan terowong anging subsonik. Tambahan pula, kajian ini akan cuba untuk mengukur pengubahan bentuk membran airfoil dengan menggunakan prinsip Young’s modulus. _______________________________________________________________________________________________________ Membrane airfoil is said to have the flexibility to change its surface geometry to adapt to the airflow. This means that it has the potential to balance the pressure gradient, resulting with a delayed stall and also the capability to expand its camber to increase the overall lift. The paper aims to study the aerodynamic performance of a ribbed-structure airfoil (NACA 4412) wrapped in a thin sheet of latex rubber membrane and compare it with the original rigid airfoil. The results from this experiment showed that the lift-to-drag ratio of the membrane airfoil improved when compared to its rigid counterpart with investigations carried out at low Reynolds number from around Re = 30,000 ∼100,000. Due to the characteristics of the membrane being frail, high flow velocity will not be suitable. Aerodynamic forces are measured using external force balance at subsonic wind tunnel. Also, this study will attempt to measure the membrane deflections of the airfoil using the concept of elastic modulus.

Contributor(s): Chan Min Xhao - Author Primary Item Type: Final Year Project Identifiers: Accession Number : 875007953 Language: English Subject Keywords: Membrane; airfoil; flexibility First presented to the public: 6/1/2018 Original Publication Date: 10/30/2018 Previously Published By: Universiti Sains Malaysia Place Of Publication: School of Aerospace Engineering Citation: Extents: Number of Pages - 75 License Grantor / Date Granted:   / ( View License ) Date Deposited 2018-10-30 16:15:20.682 Date Last Updated 2019-01-07 11:24:32.9118 Submitter: Mohd Jasnizam Mohd Salleh

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